Results from two years of trials at the Kansas State University Southeast Agricultural Research Station at Parsons confirm the viability of double-cropped sunflower in that part of the state. Conducted by recently retired KSU agronomist James Long, the trials looked at oil-type sunflower under multiple planting dates and populations.

Located in the far southeastern corner of Kansas, Parson has average annual precipitation in the neighborhood of 40 inches. The 2008 growing season was abnormally wet, with excessive wind and rain from remnants of late-summer hurricanes to the south. Final rainfall amounts for 2008 were nearly 20 inches above normal. The 2009 season also was wet and cool later on, contributing to the presence of Alternaria and Septoria leafspot.

In the 2008 double-crop sunflower trial, the oil hybrid was planted on July 3, July 15 and August 3. The replicated trials were overplanted, then thinned to final per-acre stand counts of 15,000, 20,000, 25,000, 30,000 and 35,000. Harvest took place on October 2, October 28 and November 21, respectively, for the three planting dates.

The best yield — 1,500-plus lbs/ac — came from the 20,000 population at the July 3 planting date and the 15,000 population with the July 15 planting. The August 4 planting, delayed by cool weather, had a top yield of 1,076 lbs/ac at the 15,000 population.

The 2009 Parsons trials employed the same plant populations and very similar planting dates (July 1, July 15 and July 31).

Yields were much better across all three planting dates — but particularly the early and mid-July ones. The highest yield for the July 1 planting was 3,122 lbs/ac at the 20,000 population level. For the July 15-planted plots, the 15,000 population yielded 3,063 lbs. At 1,245 lbs, the 15,000 population had the top yield for the July 31 planting.

“Sunflower has the potential to provide a late-planted double crop in southeast Kansas,” Long states. “Soybeans are normally planted after winter wheat is harvested; however, sunflower gives us another option — especially when it gets too late to plant soybeans.

“Sunflower may also allow the chance to plant a crop after wheat outside of the traditional double-crop areas, such as northern counties in our region where wheat comes off later; or in drier western counties where the aggressive root system allows sunflower to compete for the limited rainfall.”